Racism is the belief that one race can be inherently superior to another.

Not a complete definition, but I'm willing to work with that in the confines of this conversation.

You can be ignorant of racism's true impact without being racist.

Not in the context of an American adult voting for Trump. There is nothing subtle about Trump's racism. It's like that Ohio Trump delegate yesterday who said racism didn't exist until Obama came into office: that type of blindness and ignorance is impossible to cultivate unless you are racist.

Many people believe that the media is perpetuating the illusion that racism is still a major problem... Many people believe that the majority of black people are totally fine.. etc

Yes, and you have to be a flaming racist to believe these things as an American adult in 2016.

I mean this in a very practical, logistical sense.

In order to believe these things, you have to watch white supremacist TV and/or listen to white supremacist radio and/or hang out on white supremacist sites on the internet and/or be part of white supremacist communities IRL (family, friends, etc). There is no other way to get these beliefs.

There is nobody in this country who woke up one day and thought up these patently untrue thoughts on their own: this stuff is learned. There is no Oakland-hippie radio program that peddles these ideas. There is no crunchy-organic-granola-mom yoga groups that just so happens to teach you these things. There is no black Baptist church preaching this message to its black congregation on Sunday.

I repeat: practically and logistically speaking, there is no other bubble in America that allows you to believe those things EXCEPT for the bubble of white supremacist communities. Anyone who believes these things is 100% guaranteed to be part of at least one white supremacist community IRL or online. In other worst, racism is a prerequisite for even coming into contact with these beliefs.